The present invention relates to barring and other devices used to rotate the crankshaft and move other components of an engine. The present invention also relates to devices that assist in properly timing an engine, its ignition and valve settings.
Engines are built to endure many hours of maintenance free service. These engines, however, do require repair and general maintenance. Some repairs are timing related problems, which require positioning the crankshaft and related components in a particular relationship to each other. In most instances the crankshaft is rotated to obtain this relationship, wherein the crankshaft is aligned with a marking or indicators located on the engine. If an engine is rebuilt, there also exists a need for a tool to easily rotate the crankshaft during installation of other engine components or to insure that previously installed components are functioning properly.
Most automotive engines have a harmonic balancer mounted or coupled to the crankshaft. The harmonic balancer, which functions as a vibration damper, is a device connected to the crankshaft front end to lessen the torsional vibration. When the cylinders fire, power gets transmitted through the crankshaft. The front of the crankshaft takes the brunt of this power, so it often moves before the rear of the crankshaft. This causes a twisting motion. Then, when the power is removed from the front, the halfway twisted shaft unwinds and snaps back in the opposite direction. Although this unwinding process is quite small, it causes “torsional vibration.” To prevent this vibration, a harmonic balancer is attached to the front end of the crankshaft. The balancer is made of two pieces connected by a rubber sleeve or an outer portion pressed on over a rubber sleeve. When the power derived from ignition in a cylinder hits the front of the crankshaft, it tries to twist the heavy part of the damper, but ends up twisting the rubber sleeve connecting the two parts of the damper. The front of the crank can't speed up as much with the damper attached; the force is used to twist the rubber and speed up the damper wheel. This keeps the crankshaft operation calm.
However, some cars, especially custom made or designed cars, or specialty cars, may not have a harmonic balancer. Removal of the harmonic balancer can potentially improve power and performance.
In both engines with a harmonic balancer and engines without a harmonic balancer, it is possible that the timing, ignition, or valve settings may need to be adjusted and crankshaft rotated for the engine to run properly. Individual engine turning devices have been contemplated and designed to assist in proper timing functions. However, these barring devices are designed to work specifically with or specifically without a harmonic balancer. If the device is designed for the opposite arrangement, it is not helpful. That is, a device for use when the harmonic balancer is connected to the engine is not useful on an engine that does not have a harmonic balancer attached and vice versa. Thus, it would be useful to design a tool that is capable of assisting timing functions in either situation.